An approach to improve the pump-to-signal transfer efficiency of the fiber optical parametric amplifier (FOPA) is proposed and experimentally demonstrated. A fiber Bragg grating (FBG) with the Bragg wavelength at 15501nm is introduced between two high nonlinear fibers (HNLFs) to reduce the first-order idler wave, which lead to the alteration of the relative power and relationships between the involved waves. And the output power of the signal is approximately 10dB increased compared with the absence of the FBG.